diff --git a/IkiWiki/Plugin/po.pm b/IkiWiki/Plugin/po.pm
index 00c58fbe5..759e812e6 100644
--- a/IkiWiki/Plugin/po.pm
+++ b/IkiWiki/Plugin/po.pm
@@ -133,6 +133,7 @@ sub checkconfig () {
 				      $field, 'po'));
 		}
 	}
+	delete $config{po_slave_languages}{$config{po_master_language}{code}};;
 
 	map {
 		islanguagecode($_)
@@ -174,7 +175,6 @@ sub checkconfig () {
 		if ($config{po_master_language}{code} ne 'en') {
 			# Add underlay containing translated source files
 			# for the master language.
-print STDERR "added underlay locale/$config{po_master_language}{code}/$underlay\n";
 			add_underlay("locale/$config{po_master_language}{code}/$underlay")
 				if -d "$config{underlaydirbase}/locale/$config{po_master_language}{code}/$underlay";
 		}
diff --git a/debian/changelog b/debian/changelog
index 113138358..208578527 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -25,6 +25,8 @@ ikiwiki (3.20100410) UNRELEASED; urgency=low
   * Update dependency for git-core to git transition.
   * po: Check that translated underlay directories exist before using them
     for master language.
+  * po: Configuring the same language as master and slave confuses processing;
+    so filter out such a misconfiguration.
 
  -- Joey Hess <joeyh@debian.org>  Sun, 04 Apr 2010 12:17:11 -0400